In a bed arrangement, a support is provided to act on the weight or part of the weight of a user, wherein the bed distributes the weight from the body of the user over a part of a surface of the device. Depending on how the bed distributes the weight of the user, the bed will appear as being either soft or firm. The degree of firmness of such a bed is dependent on the properties of the elastic elements, such as the spring constant, and how the elastic members have been mounted in the bed, such as the degree of clamping or pre-tensioning. Thus, the firmness of the bed is normally set at the manufacturing of the device.
However, different persons wish and require different firmness. Further, different body parts may require different firmness.
It is known to provide bed arrangements with variable firmness. By inducing deformation to the elastic members to different degrees, the firmness of the device is adjustable. The deformation member has the ability to deform the elastic member independently from the deformation of the elastic member induced by the being. This means that the firmness of the bed is adjustable during initialization, according to the wishes of the user. It is also possible to compensate the firmness of the device for possible changes in the elastic properties of the elastic arrangement over time. Still further, it is known to vary the firmness independently in various zones/sections in a mattress.
Such known solutions are e.g. disclosed in EP 2 245 967 and WO 2009/120270. Both these documents also discloses the possibility of sensing the pressure being applied on different zones, and to control the firmness of different zones automatically, in order to lower the overall pressure.
However, what firmness of the various zones that is experienced as being most comfortable varies significantly from user to user. Thus, an overall minimization of the pressure will for many users not provide the most comfortable setting. Further, the pressure distribution being applied to a mattress varies significantly depending on the lying position of the user, and a user will often tend to request both different firmness distributions between the zones and different overall firmness/softness of the mattress in different lying positions.
It is therefore still a need for a bed arrangement which may automatically adjust the firmness in order to provide a more comfortable bed, and thereby to provide a more relaxing and healthy rest and sleep, and in a relatively cost-efficient way.